Shield member for an explosive actuated tool



2,932,031 4/1960 Rcymond. 227/11 FOREIGN PATENTS 1,065,856 1/1954 France..i............... 227/11 Primary Examiner-Granville Y. Custer, Jr. Altorneys-Channing L. Richards. Dalbert U. Shefte and Francis M. Pinckney ABSTRACT: A shield member for an explosive-actuated studdriving tool having a barrel member from which the tip end of the stud element extends for striking against a work surface to tire the tool, the shield member including a main body portion engaging the end of the barrel member, and a flexible 227/11 peripheral skirt portion of elastomeric material extending out- Bzsc H18 wardly beyond the tip end of the stud element for forming the 227/8 l sidewall of a closed chamber about the tip end of the stud ele- 147 ment when it is placed in contact with the work surface, the skirt portion being sufficiently flexible to permit such contact and to permit the tool to move against the work surface and be fired. The main body portion may include a barrel extension 227/147 element having a tubular projection seated in an enlargement 227/11 in the end of the barrel member bore and having a central 227/ 10 channel forming a continuation of the barrel member bore, 227/11 the central channel having an enlarged outer end for seating 227/11 therein a guide washer carried by the stud element.

James F. Helderman York,Pa. AppLNo. 727,945 Filed May 9, 1968 Patented Dec.l5,l970' [73] Assignee U.S. Expansion Bolt Company York,Pa. a corporation of Pennsylvania ACTUATED TOOL 12 Claims, 4 Drawing Figs.

Int.Cl................

References Cited UNITED STATES PATENTS 1/1941 Newell 6/1954 Erickson et a1. 2,724,116 11/1955 Termet..............

1/1957 Hilti United States Patent [72] Inventor [54] SHIELD MEMBER FOR AN EXPLOSIVE [51] [50] FieldofSearch............................................

2,773,259 12/1956 Broughtonetal. 2,775,762

SHIELD MEMBER FOR AN EXPLOSIVE ACTUATED TOOL BACKGROUND OF THE INVENTION This invention relates to explosive-actuated tools of the type described and claimed in US. Pat. No. 3,172,123, and copending Pat. application Ser. No. 726,088, filed May 2, 1968, in which a fastener such as a stud element is positioned in the bore formed in the barrel member of the tool with the tip end of the stud element extending outwardly beyond the barrel member whereby the tool is fired by striking the barrel while the tip end of the stud element is held against a work surface to cause forceful inward movement of the stud element in the bore for ignition impact against an explosive charge, with the resulting explosion driving the stud element into the work surface. 1

Explosive actuated tools by nature present something of a hazard because ignition of the explosive charge generates a rapid expansion of gases which rush out of the end of the bore as the stud element is driven therefrom,- and these gases pick up small particles of the work surface material created by impact of the stud element therewith. Consequently, it is desirable to restrict harmful propagation of the gases and entrained particles from the area immediately surrounding the end of the tool.

While there are a number of prior artdisclosures which include shield structures for conventional explosive-actuated tools, as for example U.S. Pat. No. 2,705,323 and US. Pat. No. 2,775,762, these shield structures are. substantially rigid and are mounted in fixed relation on the barrel member of the tool. Therefore, since the barrel member of the aforementioned tool associated with the presentinvention must move toward the work surface to ignite the explosive charge while the shield member is in place, these prior art shield structures would be unsuitable for use on such a tool because they would not permit such movement of the barrel member.

One solution to this problem has been to mount a rigid shield member onthe barrel member 'of the tool for relative movement therewith as described in the aforementioned US. Pat. No. 3,172,123, and while this arrangement provides a satisfactory shield for the tool, it requires an additional structural arrangement to provide the necessary relative movement.

By the present invention, a shield member is provided which permits movement of the barrel member toward the work sur-- face to fire the tool, yet which is extremely simple in construction and operation. In addition,.the shield of the present invention may include means for extending the effective length of the barrel member bore so that itcan accommodate stud elements having a length which is greater than that of stud elements for which the tool was originally designed to accom .modate.

SUMMARY OF THE INVENTION The shield member of the present invention is mounted at l the end of the barrel member of an explosive-actuated tool of the type previously referred to in which a stud element is disposed with the tip end thereof extending outwardly beyond the barrel member, and the shield member is'designed to contact the work surface into which the stud element is to be driven and to form therewith a closed chamber about the extending tip end of the stud element to restrict the propagation of the aforementioned gases and entrained particles resulting from the ignition of the explosive charge that drives the stud element. This shield member includes a flexible peripheral skirt portion of elastomeric material extending outwardly beyond the tip end ofthe stud element for engaging the work surface so as to form the sidewall of the closed chamber when the tool is positioned with the stud element tip end in abutment with the work surface preparatory to firing the tool, the flexibility of the skirt portion also allowing it to deform sufficiently to permit the tool to move against the work surface for causing inward movement of the stud element to fire the tool while, at the same time, maintaining work surface contact. Thus, the skirt portion initially flexes at the extending end thereof when the tool is initially positioned with the stud element tip end abutting the work surface before the tool is fired to positively engage the work surface in sealing relation therewith, and then flexes additionally when the barrel member is moved toward the work surfaceto effect firing of the tool whereby the skirt will remain continuously in contact with the work surface throughout the firing operation to maintain the integrity of the closed chamber formed thereby.

In the preferred embodiment of the present invention, the shield member includes a generally cylindrical main body portion having a longitudinal opening therein to receive the barrel member of the tool, one end of the main body portion presenting a flat surface portion extending in-a plane substantially perpendicular to the longitudinal axisof the stud element and spaced inwardly from the extending tip end of the stud element to form an end wall of the aforementioned closed chamber, and the flexible skirt portion normally flares outwardly from the periphery of this main body portion surface toward the work surface whereby the closed chamber will be formed when the skirt portion engages the work surface.

The shield member of the present invention may also be constructed to include a barrel extension element disposed in longitudinal alignment with the barrel'member bore of the tool when the shield member is mounted in place whereby the effective length of the barrel member bore will be increased and the tool will be capable of use with stud elements having a greater length than the stud element for which the tool was originally designed. The outer end of the barrel member bore of the tool is generally enlarged to accommodate the guide washer associated with the stud element, and the barrel extension element is provided with a tubular projection formed for telescopic reception in this enlarged portion of the barrel member bore so as to align properly the barrel extension element with the barrel member bore and to eliminate the enlargement of the barrel member bore since such enlargement will not be needed with a longer stud element having a guide washer located near the outer end thereof. The barrel extension element is further provided with a central channel extending longitudinally thercthrough for forming a continuation of the barrel member bore, and this channel may be enlarged at its outer end in correspondence with the enlargement of the barrel member bore whereby it will accommodate the guide washer on the outer end of the longer stud element to be used with the tool when the barrel extension element is employed.

If the enlargement of the barrel member bore is formed with a frustoconical surface configuration to cause wedging of the stud element guide washer as described in detail in the aforementioned Pat. application Ser. No. 726,088, then the exterior surface of the tubular projection of the barrel extension element should have a complementary configuration to insure a snug nesting thereof in the barrel member bore, and the enlarged portion of the channel in the barrel extension element may be formed with a frustoconical surface configuration corresponding to the configuration of the barrel member bore enlargement whereby it will also cause wedging of the guide washer of the longer stud element.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view illustrating one embodiment of a shield member according to the present invention;

FIG. 2 is a side elevation view of an explosive-actuated tool having a shield member of the type illustrated in FIG. I mounted thereon;

FIG. 3 is a side elevation view of an explosive actuated tool fitted with modified shield element provided with a barrel extension element; and

FIG. 4 is a side elevation view similar to FIG. 3 illustrating the position of the tool and attached shield member just after the tool has been fired.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIGS. 1 and 2 of the accompanying drawings, there is illustrated a shield member 10 embodying one form of the present invention, and in FIG. 2 the shield member 10 is shown mounted at the end of an explosive-actuated tool 12 of the type disclosed in the aforementioned U.S. Pat. No. 3,172,123. This tool 12 includes a barrel member 14 provided with a convenient rubber grip l and having a central bore 16 formed in the barrel member 14 to receive a cartridge 18 with the ignition rim 20 thereof facing outwardly in the bore 16, and to receive a stud element 22 having a protuberance 24 at its upper end face and a guide washer 26 carried on the shank of the stud element 22 by a friction fit wherewith, the outermost end portion 28 of the bore 16 being enlarged to accommodate the guide washer 26. The pointed tip end 30 of the stud element 22 extends outwardly beyond the end of the barrel member 14 whereby the tool 12 may be held with this tip end 30 in contact with a work surface 32 (shown in dashed lines in FIG. 2) while the topface of the barrel member 14 is struck with a hammer or similar implement to cause inward movement of the stud element 22 in the bore 16 which forces the protuberance 24 against the cartridge 18 to ignite the same and thereby generating expanding gases which drive the stud element 22 from the bore 16 and into the work surface 32, all as explained in greater detail in the aforementioned U.S. Pat. No. 3,172,123.

The shield member is composed of a suitable elastomeric material such as solid rubber of grade 85 Durometer, and includes a generally cylindrical main body portion 34 formed with a cylindrical longitudinal opening 36 extending therethrough and dimensioned to receive the end of the barrel member 14 in frictional engagement therewith as illustrated in FIG. 2, the bottom surface 38 of the main body portion 34 extending in a plane containing the end face of the barrel member 14 so as to be spaced inwardly from the extending tip end 30 of the stud element 22. The shield member 10 also includes a skirt portion 40 that flares outwardly from the periphery of the bottom surface 38 at an angle of approximately 45 with respect to the longitudinal axis of the tool bore 16, and that normally extends beyond the extending tip end 30 of the stud element 22 as illustrated by the full line position thereof in FIG. 2. The skirt portion 40 is relatively thin in cross section so that it is very flexible.

When the tool 12 is initially positioned with the extending tip end 30 of the stud element 22 held against a work surface 32 preparatory to firing the tool I2, the peripheral skirt portion 40 partially flexes so that the portion thereof that normally extends beyond the stud element tip end 30 will assume a bent disposition as shown by the dotted lines in FIG. 2 whereby it positively engages the work surface 32 to form a sealed peripheral sidewall of a closed chamber 42 about the stud element tip end 30, the top and bottom walls of the closed chamber 42 being provided by the bottom surface 38 of the main body portion 34 and by the work surface 32, respectively. Whenthe tool 12 is fired, the barrel member 14 thereof is struck by a hammer or similar implement and moved toward the work surface 32 causing inward movement of the stud element '32 and ignition of the cartridge 18 thereby. During this movement of the barrel member 14 toward the work surface 32, the resilient skirt portion 40 flexes further to permit such movement while continuously engaging the work'surface 32. Thus, it will be observed that the peripheral skirt portion 42 maintains the integrity of the closed chamber 42, notwithstanding the movement of the barrel member 14 with respect to the work surface 32, so as to contain properly the rush of expanding gases resulting from the ignition of cartridge 18 during firing of the tool 12, even to the point of permitting the tool 12 to be moved toward the'work surface 32 until the shield member bottom surface 38 is flush thereagainst as seen in FIG. 4 which, although directed to another embodiment of the present invention, properly illustrated the flush disposition of the shield member skirt portion.

In FIGS. 3 and 4, there is illustrated atool 12 having a modified shield member 10 mounted thereon which, in addition to providing a closed chamber about the stud element tip end as in the previously described embodiment, also serves to adapt the tool 12' for use with stud elements having a longer length than the stud elements for which the tool I0 was originally designed. To facilitate discussion of the embodiment shown in FIGS. 3 and 4, the components thereof which are substantially the same as in the previously described embodiment, have been identified by the same reference numeral used in the previously described embodiment together with a prime symbol.

The main body portion 34' of the modified shield member 10 extends beyond the end of the barrel member 14 when the latter is received and frictionally held in the longitudinal opening 36' of the shield member 10', and this extending portion of the main body portion 34 is molded to a barrel extension element 44 aligned with the longitudinal opening 36' and provided with a central channel 46 so that when the shield member 10' is placed on the tool 12 the central channel '46 will be aligned with the bore 16' of the tool I2 and will form a continuation thereof. The barrel extension element 44 is provided at its innermost end with a generally tubular projection 48 that is formed with an exterior surface configuration corresponding to the interior surface configuration of the enlarged bore portion 50 for telescopic reception therein to locate properly the barrel extension element 44 with respect to the bore 16' and to fill the enlargement of the bore 16' at the portion 50 thereof since this enlargement will not be required to accommodate a stud element guide washer when the barrel extension member 44 is employed and a longer stud element 22 is used with the tool 12. Since the longer stud element 22 has a guide washer 26' frictionally held against the tip end 30' thereof, the central channel 46 of the barrel extension member 44 is formed with an enlarged portion 52 that has a surface configuration corresponding to the surface configuration of the enlarged bore portion 50 for receiving the guide washer 26. While the enlarged central channel portion 52 may have a cylindrical configuration like that of the enlarged bore portion 28 in the previously described embodiment (FIG. 2), it is preferably formed with an outwardly flared frustoconical configuration as illustrated in FIGS. 3 and 4 for engaging the stud element guide washer 26' to initially position the stud element 22 with the head portion thereof spaced from the firing surface of the cartridge 18 and to impose a frictional re sistance on the initial inward movement of the stud element 22' for opposing impact ignition of the cartridge 18' by the stud element 22 if the extending tip end 30' thereof is inadvertently forcefully contacted (i.e., if the loaded tool 12' is accidentally dropped so that the stud element tip end 30 strikes a hard surface such as a concrete floor), all as explained in greater detail in the aforementioned Pat. application Ser. No. 726,088, which is directed to this safety feature. Also, in the tool 12 illustrated in FIGS. 3 and 4, the enlarged portion 50 of the barrel member bore 16' has an outwardly flared frustoconical surface configuration to incorporate this safety feature in the tool 12' when it is not used with a barrel extension element 44', and the exterior surface of the tubular projection 48 has a corresponding configuration so that it will nest snuggly in the enlarged bore portion 50.

To operate the tool I2 with the modified shield member 10 mounted thereon, the cartridge 18 is first placed in the tool 12 for disposition adjacent the innermost end of the bore 16', and then the stud element 22' is inserted in the tool 12 until the guide washer 26' is engaged by the enlarged portion 52 of the central channel 46 so that the stud element head portion is spaced from the cartridge 18 and the stud element tip end portion 30 extends outwardly beyond the barrel extension member 44. The tool 12 is then held as shown in FIG. 3 with the stud element tip end 39' in contact with work surface 32, the peripheral skirt portion 40 engaging the work surface 32' just as in the previously described embodiment. The operator then strikes the top face of the barrel member 14 with a first blow from a hammer or similar implement to cause initial inward movement of the stud element 22 against the aforementioned resistance imposed by the guide washer 26' whereby the stud element 22 moves from its initial position to a prefiring position (not shown) without ignition impact of the cartridge 18, the head portion of the stud element 22' being located substantially adjacent the cartridge 18, with a corresponding reduction in the outward extent of the stud element tip end 30 as explained in the aforementioned Pat. application Ser. No. the 726,088. The tool 12' is then fired by again striking the top face of the barrel member 14 to cause further inward movement of the stud element 22 which ignites the cartridge 18', the resulting explosion driving the stud element 22 from the tool 12' and into the work surface 32' as seen in FIG. 4.

it will be noted, of course, that the resilient skirt portion 40' is continuously engaged with the work surface 32' during the entire operation of the tool l2 to maintain the integrity of the closed chamber 42' in the same manner as in the previously described embodiment.

The present invention has been described above for purposes of illustration only and is not intended to be limited by this description or otherwise except as defined by the appended claims.

lclaim:

l. in an explosive-actuated tool for driving an element such as a fastener stud, said tool including a barrel member having a bore in which an element to be driven is initially disposed with the tip end thereof extending outwardly beyond said barrel member whereby said element tip end may be positioned against a work surface for movement inwardly in the bore to ignite by impact an explosive charge carried in said bore with the resulting explosion driving said element into said work surface, the improvement comprising a shield member mounted on said barrel member and arrangedto form with said work surface a closed chamber about the extending tip end of said element, said shield member including a flexible peripheral skirt portion extending beyond said tip end of said element to engage said work surface and form the sidewall of said closed chamber when said tool is positioned with said element tip end in contact with said work surface, said skirt portion being sufficiently flexible to permit said tool to move against said work surface for causing said inward movement of said element while said skirt portion remains in work surface engagement.

2. In an explosive-actuated tool of the type described, the improvement defined in claim 1 and further characterized in that said shield member includes a generally cylindrical main body portion having a longitudinal opening therein to receive the end of said barrel member in holding relation therewith, one end of said main body portion presenting a surface thereof spaced inwardly, from the extending tip .end of said element to form an end wall of said closed chamber, and in that said skirt portion extends from the periphery of said surface.

3. in an explosive-actuated tool of the type described, the improvement defined in claim 2 and further characterized in that said skirt portion flares outwardly from the periphery of said main body surface portion at an angle of approximately 45 with respect to the longitudinal axis of said tool bore.

4. in an explosive-actuated tool of the type described, the improvement defined in claim 2 and further characterized in that said main body portion of said shield member includes a barrel extension element disposed coaxially with respect to said longitudinal opening in said main body portion and having a central channel forming a continuation of said barrel member bore whereby said tool can accommodate elements of extended length.

5. In an explosive-actuated tool of the type described in claim 4 and further characterized in that said barrel member bore has an enlarged portion at the outermost end thereof for normally receiving a guide washer carried by said element. the improvement defined in claim 4 and further characterized in that said barrel extension element includes a generally tubular rojection at the innermost end thereof extending into said enarged portion of said barrel member bore to seat said extension element therein with its channel aligned with said barrel member bore.

6. In an explosive-actuated tool of the type described, the improvement defined in claim 5 and further characterized in that said central channel in said barrel extension element is enlarged at the outermost end thereof to correspond to said enlarged portion of said barrel member bore.

7, A shield member for use with an explosive-actuated stud element driving tool having a barrel member in which a bore is formed with an enlarged portion at the outermost end thereof for accommodating the guide washer carried by a stud element to be driven by said tool, said shield member including a main body portion provided with means for mounting said shield member on the end of said barrel member, and a barrel extension element provided at its innermost end with a generally tubular projection formed for telescopic reception in said enlarged portion of said barrel member bore, said barrel member extension element also being provided with a central channel extending therethrough for forming a continuation of said barrel member bore when said tubular projection is received in said enlarged portion of said barrel member bore.

8. A shield member as defined in claim 7 and further characterized in that said main body portionis composed of elastomeric material, and in that said means for mounting said shield member on said barrel member comprises an opening in said main body portion extending coaxially with said barrel extension element and formed for frictionally engaging the end of said barrel member.

9. A shield member as defined in claim 7 and further characterized in that said central channel in said with member extension element is formed at its outermost end with an enlarged portion corresponding in size to said enlarged portion of said barrel member bore.

10. A shield member as defined in claim 9 and further characterized in that said tubular projection has an exterior surface configuration corresponding to the interior surface configuration of said enlarged portion of said barrel member bore, and in that said enlarged portion of said barrel member bore, and that said enlarged portion of said barrel member extension element has an interior surface configuration corresponding to said inter surface configuration of said enlarged portion of said barrel member bore.

11. A shield member as defined in claim 10 and further characterized in that said enlarged portion of said barrel extension element has an outwardly flared frustoconical configuration.

12. A shield member as defined in claim 7 and further characterized in that said main body portion is generally cylindrical in shape and presents an end surface extending in a plane that contains the outermost end face of said barrel extension element and that is substantially perpendicular to the axis of said barrel extension element channel, and in that a flexible skirt portion is provided which flares outwardly from the periphery of said end surface at an angle of approximately 45 with respect to said axis of said barrel extension element channel.

mg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,547,333 Dated December 15, 1970 Inventogfg) James F. Helderman It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 14, delete "wherewith" and insert therewith Column 3, line 74, delete "illustrated" and insert illustrates Column 5, line 51, delete the comma after "inwardly". Column 6, line 39,

delete "with" and insert barrel line 47, delete entire line; line 48, after "and" insert in line 50 delete "inter" and insert interior Signed and sealed this 30th day of March 1971.

(SEAL) Attest:

EDWARD M.FIETCHER, JR. WILLIAM E. SCHUYLER, JR Attesting Officer Commissioner of Patents 

